Assessment of the Daily Average Requirement of Iodine in Lactating Women

NCT05382793 | Completed DMC

• 1 other identifier: BASEC2022-00130
• Study Type: interventional
• Target: 17
• Locations: 1 country
• Sites: 1

Brief Summary

Human milk is the only source of iodine during early infancy and adequate iodine intake during lactation is necessary to assure optimal thyroid function in breastfed infants. However, the physiological requirement of iodine in lactating women is uncertain and recommendations for the daily dietary average requirement are poorly defined. WHO recommends iodine supplementation to lactating women in populations with incomplete coverage of iodized salt and deficient iodine intake, but the scientific evidence is weak and the optimal dose is uncertain. The primary objective is to assess the daily dietary average requirement for iodine in lactating women. Secondary objectives are to:

• Estimate the daily average requirement for iodine in exclusively breastfed infants;
• Assess the dose-response of dietary iodine supplements on breast milk iodine concentration in lactating women with adequate and inadequate habitual iodine intakes;
• Estimate the maternal iodine intake required to provide exclusively breastfed infants with an adequate iodine intake via breast milk.

Conditions

Healthy; Iodine Deficiency

Keywords

Iodine; Dietary requirement; Lactating women; Infant

Outcome Measures

Primary Outcomes (1)

• Maternal iodine retention (μg/day)

  Calculated as iodine intake (µg/day) minus the iodine excretion (µg/day)

  24 hours

Secondary Outcomes (2)

• Maternal iodine excretion in breast milk (μg/day)

  24 hours

• Infant iodine retention (μg/day)

  24 hours

Study Arms (2)

Lactating women with assumed adequate habitual iodine intake

EXPERIMENTAL

Women who consumed iodine-containing dietary supplements during pregnancy (≥150 μg/day). Women in this group will receive a daily oral iodine supplement providing 150 μg iodine as potassium iodide for 14 days before the study start.

Dietary Supplement: Control; Dietary Supplement: Iodide (150 μg/day); Dietary Supplement: Iodine (300 μg/day)

Lactating mothers with assumed inadequate habitual iodine intake

EXPERIMENTAL

Women who did not consume iodine-containing dietary supplements during pregnancy (≥150 μg/day).

Dietary Supplement: Control; Dietary Supplement: Iodide (150 μg/day); Dietary Supplement: Iodine (300 μg/day)

Interventions

Control DIETARY_SUPPLEMENT

No iodine

Lactating mothers with assumed inadequate habitual iodine intake; Lactating women with assumed adequate habitual iodine intake

Iodide (150 μg/day) DIETARY_SUPPLEMENT

A single oral tablet once daily for five days providing 150 μg iodine as potassium iodide

Also known as: Jodetten® 150 Henning, Sanofi-Aventis Germany GmbH, Germany

Lactating mothers with assumed inadequate habitual iodine intake; Lactating women with assumed adequate habitual iodine intake

Iodine (300 μg/day) DIETARY_SUPPLEMENT

Two oral tablets (150 μg + 150 μg) daily for five days providing 300 μg iodine as potassium iodide

Also known as: Jodetten® 150 Henning, Sanofi-Aventis Germany GmbH, Germany

Lactating mothers with assumed inadequate habitual iodine intake; Lactating women with assumed adequate habitual iodine intake

Eligibility Criteria

• Age: 18 Years - 49 Years
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Consent to enroll herself and her baby;
• Age 18 to 49 years;
• Singleton pregnancy;
• Exclusively breastfeeding;
• Self-estimated BMI \<30 kg/m2 before conception.

You may not qualify if:

• TSH \>6 mIU/L;
• Anemia (Hb \<11.7 g/L);
• Pregnancy (self-reported);
• Acute illness (e.g. gastroenteritis);
• History of thyroid disease, diabetes, metabolic disease or inflammatory bowel disease (self-reported);
• Currently smoking (\>1 cigarette/day);
• Drug abuse or extensive alcohol intake;
• Exposure to iodine-containing X-ray or computed tomography contrast agents during the past 6 months;
• Adenomatous goiter, dermatitis, anti-C1q-vasculitis.
• Infants
• Full term (38-42 weeks);
• Birthweight ≥2.5 kg;
• Exclusively breastfed;
• Age 0-10 weeks at recruitment.
• Age \>6 months;

Sponsors & Collaborators

• University Children's Hospital, Zurich: lead
• ETH Zurich (Switzerland): collaborator

Study Sites (1)

Nutrition Research Unit, University Children's Hospital Zurich

Zurich, 8032, Switzerland

Location

MeSH Terms

Interventions

Iodides; Iodine

Intervention Hierarchy (Ancestors)

Anions; Ions; Electrolytes; Inorganic Chemicals; Iodine Compounds; Halogens; Elements

Study Officials

• Christian Braegger, M.D.

  University Children's Hospital, Zurich

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Single-center, randomized, controlled, dose-response metabolic balance study with cross-over design

Study Record Dates

• First Submitted: May 16, 2022
• First Posted: May 19, 2022
• Study Start: May 6, 2022
• Primary Completion: December 15, 2023
• Study Completion: December 15, 2023
• Last Updated: September 3, 2025

Record last verified: 2025-08

Locations

CH (1)